308  MISCELLANEOUS  CHEMICAL  OBSERVATIONS. 
The  experiments  with  saccharine  and  alcoholic  solutions  of 
iodide  of  iron  do  prove  the  fact  that  sugar  is  a  better  preserving 
agent  against  oxidation  than  alcohol ;  and  were  not  cited  for 
any  other  purpose.  Mr.  Thayer's  example  does  not  place  the 
two  liquids  in  like  conditions,  inasmuch#as  a  pint  of  syrup  is  un- 
able to  dissolve  one  ounce  of  oil  of  lemon. 
I  am  fully  aware  that  the  value  of  chemical  and  pharmaceu- 
tical investigations  is  not  affected  by  the  locality  where  they  are 
originated.  My  views  were  formed  in  experimenting  to  conquer 
difficulties,  they  are  based  upon  theory  and  experience,  and 
therefore  I  think  that  I  am  not  much  to  blame  if  I  adhere  to 
them,  until  the  theoretical  ground  as  well  as  the  facts  shall  have 
been  overthrown. 
MISCELLANEOUS  CHEMICAL  OBSERVATIONS. 
By  Dr.  John  T.  Plummer. 
[The  following  letter  received  from  our  friend  Dr.  Plummer  is  so  cha- 
racteristic of  his  observing  habit  of  mind,  that,  though  not  intended  for 
publication,  we  feel  best  satisfied  to  make  that  disposition  of  it.  The  reac- 
tion with  urine  will  be  of  interest  to  medical  men.  The  blue  coloration  with 
guaiacum  is  produced  by  various  substances,  like  gluten,  arabin,  and  the 
gummy  juices  of  fresh  roots  like  the  potato  and  carrot.  Whether  animal 
mucus  has  the  same  effect  we  do  not  know. — Editor.] 
Richmond,  Indiana,  &  mo.  23c?,  1859. 
Esteemed  Friend, — Some  time  ago,  after  filtering  out  a 
large  amount  of  what  appeared  to  be  mucus,  from  the  urine  of 
an  adult  patient,  (perhaps  65  years  of  age,)  and  who  was  af- 
flicted with  a  renal  or  cystic  complaint,  I  applied  to  it  a  few 
drops  of  tincture  of  guaiacum,  and  obtained  a  rich  Prussian 
blue  color.  That  there  might  be  no  mistake  in  the  case,  I  re- 
peated the  experiment  day  after  day,  under  varying  conditions, 
and  always  and  with  certainty  obtained  the  same  result.  This, 
it  may  be  recollected,  is  Schonbein's  method  of  detecting  the 
presence  of  ozone,  (which  he  considers  active  oxygen)  in  mush- 
rooms, the  metallic  oxide,  &c.  My  application  of  the  tincture 
in  this  case  was  for  another  purpose,  and  meeting  with  this  un- 
looked  for  result,  I  placed  it  among  my  memoranda,  thinking 
some  day  it  might  be  of  some  pathological  value.    As  it  may  be 
